Phenolic resin molding compound

ABSTRACT

A phenolic resin molding compound includes (A) a novolac-type phenolic resin including an alkylbenzene-modified novolac-type phenolic resin, (B) a resol-type phenolic resin, (C) hexamethylenetetramine, (D) graphite, and (E) fiber-shaped filler, wherein in regard to the content of each component on the basis of the entirety of the molding compound, a total content of the components (A) to (C) is 30 to 40% by weight, a content of the component (D) is 30 to 50% by weight, and a content of the component (E) is 5 to 20% by weight.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional Application of U.S. patent applicationSer. No. 13/603,831, filed on Sep. 5, 2012, which claims the benefit ofpriority of Japanese Patent Application No. 2011-193712, filed on Sep.6, 2011, the entire contents of which are incorporated herein byreference.

BACKGROUND

1. Technical Field

The invention relates to a phenolic resin molding compound.

2. Related Art

Hitherto, there has been a demand for heat resistance and abrasionresistance in mechanical parts that are used in vehicles and the like.As a material that satisfies these characteristics, parts formed fromceramic or metal have been used in mechanical parts in the related art.However, the mechanical parts formed from ceramic or metal have variousproblems in that the weight thereof is heavy, it takes a long time forprocessing, the cost is high, and the like. As means for solving theseproblems, mechanical parts formed from plastic material have attractedattention from a viewpoint of weight reduction of the parts.

As a material that is used in the case of forming the mechanical parts,among plastic materials, particularly, a phenolic resin molding compoundhas attracted attention from a viewpoint of heat resistance or abrasionresistance. The mechanical parts that include the phenolic resin moldingcompound are superior in that the weight thereof is lighter, processingis easier, and heat resistance is higher compared to mechanical partsformed from ceramic or metal. In addition, to give heat resistance andmechanical strength to the mechanical parts, glass fiber, silica, or thelike has been used as a filling material in the related art. However, inthe case of forming the mechanical parts using the phenolic resinmolding compound, when the filling material such as the glass fiber andsilica is used, the mechanical strength is improved, but there is aproblem in that the abrasion resistance deteriorates. Therefore, in acase where the abrasion resistance is an important characteristic, thephenolic resin molding compound that is inferior in abrasion resistancemay not be used. In addition, in a case where the mechanical parts aremolded using the phenolic resin molding compound, since dimensionalchange may easily occur, there is a problem in that the dimensions ofthe mechanical parts are not maintained within a tolerance, and a yieldratio deteriorates.

A precision part may absorb moisture and swell, such that operationfailure may be caused. Therefore, it is necessary to make dimensionalstability under high humidity excellent.

As technologies of improving an abrasion characteristic and waterresistance of a mechanism part that is molded using a phenolic resinmolding compound, technologies described in Japanese Unexamined PatentPublication Nos. 2005-47971, 2005-265033, and 2011-68705 have beendisclosed.

Japanese Unexamined Patent Publication No. 2005-47971 discloses atechnology of improving an abrasion characteristic by blending graphitethat is a solid lubricant to a phenolic resin molding compound.

Japanese Unexamined Patent Publication No. 2005-265033 discloses atechnology of improving an abrasion characteristic and a mechanicalcharacteristic by using glass fiber in combination in addition tographite. In the technology disclosed in Japanese Unexamined PatentPublication No. 2005-265033, in regard to contents of the graphite andglass fiber on the basis of the entirety of the molding compound, thecontent of the graphite is 5 to 20% by weight and the content of theglass fiber is 40 to 60% by weight.

Japanese Unexamined Patent Publication No. 2011-68705 discloses atechnology of improving dimensional accuracy and dimensional stabilitywith heat resistance and moisture resistance by blending analkylbenzene-modified novolac-type phenolic resin and glass fiber. Inthe technology disclosed in Japanese Unexamined Patent Publication No.2011-68705, on the basis of the entirety of the molding compound, atotal content of (A) a novolac-type phenolic resin including thealkylbenzene-modified novolac-type phenolic resin, (B) a resol-typephenolic resin, and (C) hexamethylenetetramine is 15 to 30% by weight,and a content of the glass fiber is 10 to 20% by weight.

SUMMARY

However, in the technology disclosed in Japanese Unexamined PatentPublication No. 2005-47971, in a case where the graphite is merely usedas the filling material, since the mechanical strength becomes low, amolded article is brittle, and thus cracking may easily occur. Inaddition, the technology disclosed in Japanese Unexamined PatentPublication No. 2005-265033 may not be sufficient from a viewpoint ofwater resistance. In addition, the technology disclosed in JapaneseUnexamined Patent Publication No. 2011-68705 may not be sufficient froma viewpoint of abrasion resistance.

An object of the invention is to provide a phenolic resin moldingcompound in which an abrasion characteristic and mechanical strength arebalanced to a high degree, and which is excellent in water resistance.

The present inventors have extensively studied with respect to kinds ofcomponents contained and blending amounts thereof so as to provide aphenolic resin molding compound that has an excellent abrasioncharacteristic, mechanical strength, and water resistance with a goodbalance. As a result thereof, the present inventors have found that whenfive components of (A) a novolac-type phenolic resin including analkylbenzene-modified novolac-type phenolic resin, (B) a resol-typephenolic resin, (C) hexamethylenetetramine, (D) graphite, and (E) afiber-shaped filler are blended in a specific blending amount,respectively, it is effective as a design guideline, and the inventionis accomplished.

In an embodiment, there is provided a phenolic resin molding compoundincluding (A) a novolac-type phenolic resin including analkylbenzene-modified novolac-type phenolic resin, (B) a resol-typephenolic resin, (C) hexamethylenetetramine, (D) graphite, and (E) afiber-shaped filler, wherein in regard to the content of each componenton the basis of the entirety of the molding compound, a total content ofthe components (A) to (C) is 30 to 40% by weight, a content of thecomponent (D) is 30 to 50% by weight, and a content of the component (E)is 5 to 20% by weight.

According to the invention, it is possible to provide a phenolic resinmolding compound which an abrasion characteristic and mechanicalstrength are balanced to a high degree, and which is excellent in waterresistance. Therefore, the phenolic resin molding compound relating tothe invention may be appropriately used as a gas meter part (adistribution chamber or a valve), or a sliding part such as a vane pumppart of a vehicle.

DETAILED DESCRIPTION

The invention will be now described herein with reference toillustrative embodiments. Those skilled in the art will recognize thatmany alternative embodiments can be accomplished using the teachings ofthe present invention and that the invention is not limited to theembodiments illustrated for explanatory purposes.

Hereinafter, a phenolic resin molding compound (hereinafter, may besimply referred to as “molding compound”) of the invention will bedescribed in detail.

First, in a case where the phenolic resin molding compound is molded tobe used as a gas meter part (a distribution chamber or a valve), or asliding part such as a vane pump part of a vehicle, it is necessary forthe phenolic resin molding compound to exhibit properties such as lowfriction with a counter material, that is, a high sliding property (i),high mechanical strength allowing a use for a vehicle (ii), and nodimensional change even in a high-humidity conditions or in a state ofbeing dipped in water, that is, high water resistance (iii),respectively.

A molding compound relating to this embodiment is a phenolic resinmolding compound including (A) a novolac-type phenolic resin includingan alkylbenzene-modified novolac-type phenolic resin, (B) a resol-typephenolic resin, (C) hexamethylenetetramine, (D) graphite, and (E) afiber-shaped filler, wherein in regard to contents of respectivecomponents on the basis of the entirety of the molding compound, a totalcontent of the components (A) to (C) is 30 to 40% by weight, a contentof the component (D) is 30 to 50% by weight, and a content of thecomponent (E) is 5 to 20% by weight. In this manner, when the respectivecomponents (A) to (E) are blended in a specific ratio, it is possible toobtain a phenolic resin molding compound which an abrasioncharacteristic and mechanical strength may be balanced to a high degree,and which is excellent in water resistance.

Hereinafter, respective components that are blended into the phenolicresin molding compound relating to this embodiment and blending amountsthereof will be described.

First, (A) the novolac-type phenolic resin including analkylbenzene-modified novolac-type phenolic resin is blended into themolding compound relating to this embodiment.

Here, the alkylbenzene-modified novolac-type phenolic resin represents aresin which an alkylbenzene such as xylene and toluene is bonded to anovolac-type phenolic resin with methylene bonding or the like. Whenthis alkylbenzene-modified novolac-type phenolic resin is blended intothe molding compound, water resistance and heat resistance may beincreased while maintaining the mechanical strength at a practical-uselevel compared to a case in which a common novolac-type phenolic resinis blended into the molding compound. The reason is because ahydrophilic hydroxyl group of a phenolic resin is substituted ahydrophobic alkylbenzene, and thus a water absorption rate of themolding compound may be reduced.

In addition, a method of producing the alkylbenzene-modifiednovolac-type phenolic resin is not particularly limited, but forexample, the following method may be used. First, an alkylbenzene andformaldehyde are made to react with each other in the presence of anacidic catalyst to produce an alkylbenzene resin. Next, the alkylbenzeneresin that is obtained is made to react with phenols or phenols andaldehydes in the presence of an acidic catalyst. In this way, thealkylbenzene-modified novolac-type phenolic resin relating to thisembodiment may be obtained. In addition, in the alkylbenzene-modifiednovolac-type phenolic resin relating to this embodiment, a modificationratio of the alkylbenzene is preferably equal to or more than 3% byweight and equal to or less than 70% by weight on the basis of the sumof the phenolic resin and an alkyl-modified novolac resin, and morepreferably equal to or more than 5% by weight and equal to or less than50% by weight. When the modification ratio is set in this way, the waterresistance and heat resistance of the molding compound may be furtherincreased, and balance between the abrasion characteristic and themechanical strength may be maintained to a high degree.

In addition, the phenols that are used at the time of producing thealkylbenzene-modified novolac-type phenolic resin relating to thisembodiment are not particularly limited, but examples thereof includephenol, o-cresol, m-cresol, p-cresol, xylenol, alkylphenols, catechol,resorcinol, and the like. In addition, these phenols may be used aloneor in combination of two or more.

In addition, aldehydes that are used at the time of producing thealkylbenzene-modified novolac-type phenolic resin relating to thisembodiment are not particularly limited, but examples thereof includealdehydes such as formaldehyde, paraformaldehyde, and benzaldehyde,materials that are sources of these aldehydes, solutions of thesealdehydes, and the like. In addition, these aldehydes may be used aloneor in combination of two or more.

In addition, examples of the alkylbenzene-modified novolac-type phenolicresin relating to this embodiment include xylene-modified novolac-typephenolic resin, toluene-modified novolac-type phenolic resin, and thelike.

In addition, in the molding compound relating to this embodiment, acontent of the alkylbenzene-modified novolac-type phenolic resin in thecomponent (A) is preferably 20 to 30% by weight on the basis of the sumof the components (A) and (B), and more preferably 15 to 25% by weight.When the content of the alkylbenzene-modified novolac-type phenolicresin is set to be equal to or more than the lower limit, a material inwhich a water-resistant dimensional change is small may be obtained, andwhen the content thereof is set to be equal to or less than the upperlimit, the mechanical strength may be set to a very appropriate level.

In addition, in the molding compound relating to this embodiment, thecomponent (A) may contain a novolac-type phenolic resin other than thealkylbenzene-modified novolac-type phenolic resin. When the novolac-typephenolic resin is contained in this way, the manufacturing cost may bereduced. Here, in the component (A), a content of the novolac-typephenolic resin other than the alkylbenzene-modified novolac-typephenolic resin is preferably 60 to 80% by weight.

In addition, as the novolac-type phenolic resin that is contained in thecomponent (A), a resin, which is commonly obtained by making phenols andaldehydes react with each other in the presence of an acidic catalystwith a molar ratio (aldehydes/phenols) of aldehydes to phenols being setto 0.7 to 0.9, may be used.

In addition, the phenols that are used at the time of producing thenovolac-type phenolic resin other than the alkylbenzene-modifiednovolac-type phenolic resin are not particularly limited, but examplesthereof include phenol, o-cresol, m-cresol, p-cresol, xylenol,alkylphenols, catechol, resorcinol, and the like. In addition, thesephenols may be used alone or in combination of two or more.

In addition, aldehydes that are used at the time of producing thenovolac-type phenolic resin other than the alkylbenzene-modifiednovolac-type phenolic resin relating to this embodiment are notparticularly limited, but examples thereof include aldehydes such asformaldehyde, paraformaldehyde, and benzaldehyde, materials that aresources of these aldehydes, solutions of these aldehydes, and the like.In addition, these aldehydes may be used alone or in combination of twoor more.

Next, (B) the resol-type phenolic resin is blended into the moldingcompound relating to this embodiment. Due to this, toughness of a moldedarticle that is obtained by molding the molding compound may beimproved, and thus the mechanical strength may be increased.

As the resol-type phenolic resin relating to this embodiment, a resin,which is commonly obtained by making phenols and aldehydes react witheach other in the presence of a basic catalyst with a molar ratio(aldehydes/phenols) of aldehydes to phenols being set to 1.3 to 1.7 maybe used.

The phenols that are used at the time of producing the resol-typephenolic resin relating to this embodiment are not particularly limited,but examples thereof include phenol, o-cresol, m-cresol, p-cresol,xylenol, alkylphenols, catechol, resorcinol, and the like. In addition,these phenols may be used alone or in combination of two or more.

In addition, aldehydes that are used at the time of producing theresol-type phenolic resin relating to this embodiment are notparticularly limited, but examples thereof include aldehydes such asformaldehyde, paraformaldehyde, and benzaldehyde, materials that aresources of these aldehydes, solutions of these aldehydes, and the like.In addition, these aldehydes may be used alone or in combination of twoor more.

Next, (C) the hexamethylenetetramine is blended into the moldingcompound relating to this embodiment. The component (C) serves as acuring agent of the component (A) together with the component (B).

In addition, a blending amount of the hexamethylenetetramine on thebasis of the entirety of the molding compound is not particularlylimited, but for example, 30 to 40 parts by weight is blended in on thebasis of 100 parts by weight of the component (A). Furthermore, in themolding compound relating to this embodiment, in addition to thehexamethylenetetramine and the component (B), a component serving as acuring agent of the component (A) may be used in combination. As thiscuring agent, for example, components such as trimethylamine andpyridine may be exemplified.

To obtain the phenolic resin molding compound relating to thisembodiment that is excellent in an abrasion characteristic, mechanicalstrength, and water resistance, and that is excellent from the viewpointof balance between these three characteristics, it is preferable thatthe total contents of the components (A), (B), and (C) be 30 to 40% byweight on the basis of the entirety of the molding compound, and morepreferably 33 to 38% by weight. When the total content of these threecomponents is set to be equal to or more than the lower limit,satisfactory workability may be secured during producing the moldingcompound, and when the total content is set to be equal to or less thanthe upper limit, a water-resistant dimensional change may be made to besmall. The reason is not clear, but it is assumed that since thehydrophobic alkylbenzene is contained in the alkylbenzene-modifiednovolac-type phenolic resin as described above, the component (B) andthe component (C) are further used in combination as a curing agent ofthe component (A), and thus a decrease in curing property may besuppressed, and the water resistance of the molding compound may beimproved. Furthermore, from the viewpoints of balance between the waterresistance, the abrasion characteristic, and the mechanical strength,when the total content of the three components is outside theabove-described range, a synergistic effect of the components (D) and(E) to be described later may not be exhibited.

Next, (D) the graphite is blended into the molding compound relating tothis embodiment. Furthermore, in the molding compound relating to thisembodiment, it is preferable that the graphite be blended in an amountof 30 to 50% by weight on the basis of the entirety of the moldingcompound, and more preferably 35 to 45% by weight. When the blending iscarried out in this way, workability becomes very appropriate duringproducing the molding compound, the abrasion characteristic may beimproved, and the balance between the water resistance, the abrasioncharacteristic, and the mechanical strength may be maintained to a highdegree. The reason is considered that the graphite is an excellent solidlubricant, and thus the graphite may decrease, particularly, a frictioncoefficient. When the graphite is contained within the above-mentionedblending ratio range, it is considered that not only the abrasioncharacteristic may be improved, but also the balance between theabrasion characteristic, the mechanical strength, and the waterresistance may be maintained to a high degree due to a synergisticeffect of the components (A), (B), (C), and (E).

Next, (E) the fiber-shaped filler is blended into the molding compoundrelating to this embodiment. Furthermore, in the molding compoundrelating to this embodiment, it is preferable that the fiber-shapedfiller be blended in an amount of 5 to 20% by weight on the basis of theentirety of the molding compound, and more preferably 10 to 15% byweight. When the blending is carried out in this way, the mechanicalstrength of a molded article may be improved. Specifically, when thefiber-shaped filler is blended into the molding compound within thecontent of above-described range, an elastic modulus and a degree ofelongation of the molded article reach a very appropriate level, andthus sufficient toughness may be secured, that is, the mechanicalstrength may be improved. Furthermore, balance between the abrasioncharacteristic and the mechanical characteristic may be satisfactory.

In addition, examples of the fiber-shaped filler relating to thisembodiment include glass fiber, carbon fiber, rock wool, and the like.Among these, it is preferable to use glass fiber. In addition, althoughit is not being particularly limited to, as the glass fiber, it ispreferable to use glass fiber having a number-average fiber diameter of10 to 15 μm, and a number-average fiber length of 1 to 3 mm, and it ismore preferable to use glass fiber having a number-average fiberdiameter of 11 to 13 μm, and a number-average fiber length of 2 to 3 mm.In this manner, workability during producing the molding compound andthe mechanical strength of a molded product that is obtained may befurther improved.

In addition, in the molding compound relating to this embodiment,various additives that are used in a common thermosetting resin moldingcompound, for example, a curing catalyst, a mold releasing agent such asstearic acid or polyethylene, an adhesiveness improving agent or acoupling agent that improves adhesiveness between a filling agent andthe thermosetting resin, a solvent, and the like may be blended inaccording to necessity.

In addition, in this embodiment, a rectangular parallelepiped testspecimen of 8×4×2 mm, which is obtained by injection-molding a granularmolding compound (a mold temperature is set to 180° C. and a curing timeis set to 15 seconds), is annealed at 160° C. for six hours and then isdipped in warm water at 80° C. for 72 hours, and a ratio of a dimensionin a 8 mm direction after being dipped with respect to a dimension inthe 8 mm direction before being dipped is set as a dimensional changeratio that is an index indicating water resistance of the moldingcompound. In addition, a unit is %. In this embodiment, the dimensionalchange ratio of the molding compound in this embodiment is preferably0.32% or less, and more preferably 0.25% or less. When the dimensionalchange ratio is within the above-described range, a molded article in astate in which all of the water resistance, the mechanical strength, andthe abrasion characteristic are excellent, and these threecharacteristics are balanced may be obtained.

In addition, a method of producing the molding compound relating to thisembodiment is not particularly limited as long as the method is used inthe related art, but for example, a method in which in addition to theraw materials, a filling agent, a curing agent, a curing catalyst, amold releasing agent, a coupling agent, and the like are blended in areuniformly mixed according to necessity, and then the resultant mixtureis heated, melted, and kneaded by using a kneader alone such as a roll,a co-kneader, and a biaxial extruder or by using the roll and anothermixing device in combination, and then this resultant kneaded materialis granulated or crushed may be used.

In addition, in the case of molding the molding compound relating tothis embodiment, injection molding is appropriately used, but it is notparticularly limited thereto, and the molding compound may be molded byanother method such as conveyance molding, compression molding, andinjection and compression molding. Even though molding conditions atthis time depend on the thickness of a molded article, for example, in acase where a molded article having the thickness of approximately 5 mm,the molding may be carried out at a mold temperature of 170 to 190° C.,at a molding pressure of 100 to 150 MPa, and for a curing time of 30 to90 seconds.

EXAMPLES

Raw material components that were used in respective example andrespective comparative example are described below.

(1) Alkylbenzene-modified novolac-type phenolic resin: “PR-TS-3”=(xyleneresin-22% modified novolac-type phenolic resin), manufactured bySUMITOMO BAKELITE CO., LTD

(2) Novolac-type phenolic resin: “A-1077P”, manufactured by SUMITOMOBAKELITE CO., LTD

(3) Resol-type phenolic resin: “R-25”, manufactured by SUMITOMO BAKELITECO., LTD

(4) Hexamethylenetetramine: “HEXAMINE”, manufactured by CHANG CHUNPETROCHEMICAL CO., LTD

(5) Graphite: “soil graphite #90”, manufactured by Nippon GraphiteIndustries, Ltd.

(6) Glass fiber: “CS3E479S”, manufactured by Nitto Boseki Co., Ltd.

(7) Calcium carbonate: “calcium carbonate SS80”, manufactured by NittoFunka Kogyo K.K.

(8) Curing auxiliary agent (magnesium oxide): “STAR MAG M”, manufacturedby Konoshima Chemical Co., Ltd.

(9) Mold releasing agent: the following two kinds were used in a ratioof 1:1 (weight ratio).

(Polyethylene: “Sun Wax”, manufactured by Sanyo Chemical Industries,Ltd.)

(Stearic acid: “stearic acid Sakura”, manufactured by NOF corporation)

Examples and Comparative Examples

With respect to Examples 1 to 5, and Comparative Examples 1 to 4, amaterial mixture, which was obtained by blending respective componentsaccording to a blending amount shown in Table 1, was kneaded usingheating rolls having a different rotational speed, the resultant kneadedmaterial was cooled in a sheet shape, and the cooled material wascrushed to obtain a granular molding compound. In addition, kneadingconditions of the heating rolls were as follows: rational speeds of ahigh-speed side and a low-speed side were set to 20 rpm and 14 rpm,respectively, temperatures of the high-speed side and the low-speed sidewere set to 90° C. and 20° C., respectively, and a kneading time was setto 5 to 10 minutes.

With respect to a molding compound that was obtained in a blending ratioshown in Table 1, the following measurement and evaluations were carriedout.

Evaluation Item

(1) Amount of abrasion: a granular molding compound wasconveyance-molded (a mold temperature was 175° C. and a curing time wasthree minutes) to prepare test specimens (a ring and a plate). Thesetest specimens were annealed at 160° C. for 6 hours and then weresubjected to an abrasion test by Suzuki-type abrasion test machine underconditions of a pressure of 5 kgf/cm2, a rotational speed of 1.194 msec,a test time of 4 hours, and a temperature of room temperature inaccordance with JISK 7218. After this abrasion test, a total amount ofabrasion of the ring and plate was evaluated. In addition, a unit wasset to mm3.

(2) dimensional change ratio: a granular molding compound wasinjection-molded (a mold temperature was 180° C. and a curing time was15 seconds) to prepare a rectangular parallelepiped test specimen of8×4×2 mm. This test specimen was annealed at 160° C. for 6 hours, andthen was dipped in warm water at 80° C. for 72 hours. Dimensions in an 8mm direction before and after the dipping were evaluated. In addition, aunit was set to %.

(3) Bending strength: a granular molding compound was injection-molded(a mold temperature was 175° C. and a curing time was one minute) toprepare a test specimen. This test specimen was annealed at 160° C. for6 hours, and then the bending strength was measured in accordance withISO 178. In addition, a unit was set to MPa.

(4) Workability: workability during producing a molding compound wasconfirmed. Symbols represent the following contents.

O: Satisfactory

X: Cured while roll kneading was insufficient, and thus blendingmaterials were not uniformly distributed due to insufficient kneading.

Evaluation results relating to the above-described evaluation items areshown in Table 1 together with blending ratios (% by weight) ofrespective components.

TABLE 1 Compara- Compara- Compara- Compara- tive tive tive tive ExampleExample Example Example Example Example Example Example Example 1 2 3 45 1 2 3 4 Component Alkylbenzene- 6 6 8 4 12 — 6 6 6 (A) modifiednovolac- type phenolic resin Novolac-type 16 16 14 18 10 22 16 16 16phenolic resin Component Resol-type 7 7 7 7 7 7 7 7 7 (B) phenolic resinComponent Hexamethylene- 7 7 7 7 7 7 7 7 7 (C) tetramine ComponentGraphite 40 30 40 40 40 40 41 38 20 (D) Component Glass fiber 12 12 1212 12 12 — 25 12 (E) Others Calcium 10 20 10 10 10 10 21 — 30 carbonateCuring catalyst 1 1 1 1 1 1 1 1 1 Mold releasing 1 1 1 1 1 1 1 1 1 agentSum 100 100 100 100 100 100 100 100 100 Amount of abrasion (mm³) 8 8 109 10 5 6 25 20 Water-resistant dimensional 0.2 0.25 0.18 0.32 0.17 0.40.25 0.25 0.35 change ratio (%) Bending strength (MPa) 100 80 90 95 6070 50 120 60 Workability ◯ ◯ ◯ ◯ ◯ X X ◯ ◯

As can be seen from Table 1, all of the molding compounds of Examples 1to 5 were superior in an amount of abrasion, water-resistant dimensionalchange, and bending strength to values of Comparative Examples, andworkability was satisfactory. Actually, in a case where sliding partsare manufactured using the molding compound described in examples,sliding parts, which any of the abrasion characteristic, mechanicalstrength, and water resistance are excellent and these are balanced to ahigh degree, were obtained.

As is clear from the results obtained from the above-described examplesand comparative examples, in the phenolic resin molding compound of theinvention, the abrasion characteristic and the strength thereof arebalanced to a higher degree and the water resistance is more excellentcompared to a phenolic resin molding compound in the related art.Therefore, the phenolic resin molding compound of the invention may beappropriately used as a molded article in which these characteristicsare required, for example, a gas meter part (a distribution chamber or avalve), a sliding part such as a vane pump part of a vehicle, and thelike.

It is apparent that the present invention is not limited to the aboveembodiment, and may be modified and changed without departing from thescope and spirit of the invention.

What is claimed is:
 1. A phenolic resin molding compound, comprising:(A) a novolac-type phenolic resin, comprising an alkylbenzene-modifiednovolac-type phenolic resin; (B) a resol-type phenolic resin; (C)hexamethylenetetramine; (D) graphite; and 0% of (E) fiber-shaped filler,wherein a total content of the components (A) to (C) is 30 to 40% byweight based on an entirety of the molding compound, wherein a contentof the component (C) is 30 to 40 parts by weight based on 100 parts byweight of the component (A), and wherein a content of the component (D)is 30 to 50% by weight based on the entirety of the molding compound. 2.The phenolic resin molding compound according to claim 1, wherein acontent of the alkylbenzene-modified novolac-type phenolic resin in thecomponent (A) is 20 to 30% by weight based on a total content of thecomponents (A) and (B).
 3. The phenolic resin molding compound accordingto claim 2, wherein the content of the alkylbenzene-modifiednovolac-type phenolic resin in the component (A) is 20 to 25% by weightbased on a total content of the components (A) and (B).
 4. The phenolicresin molding compound according to claim 1, wherein a modificationratio of alkylbenzene in the alkylbenzene-modified novolac-type phenolicresin is 3% by weight to 70% by weight.
 5. The phenolic resin moldingcompound according to claim 1, wherein in a case where a rectangularparallelepiped test specimen of 8×4×2 mm, which is obtained byinjection-molding a granular molding compound at a mold temperature of180° C. and a curing time of 15 seconds, is annealed at 160° C. for sixhours and then is dipped in warm water at 80° C. for 72 hours, when aratio of a dimension in 8 mm direction after being dipped with respectto a dimension in the 8 mm direction before being dipped is set as adimensional change ratio, the dimensional change ratio is 0.32% or less.6. A sliding part, comprising the phenolic resin molding compoundaccording to claim 1.